1. ¹Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, Paddington, London, W2 1PG, UK
2. ²HIV Vaccine Trials Network, Seattle, USA
3. ³National Public Health Institute, Finland
4. ⁴Family Federation of Finland, Finland
5. ⁵Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Finland
6. ⁶Lund University, Sweden

Correspondence: Dr KM French, E-mail: k.french@imperial.ac.uk

Received 4 October 2006; Revised 29 November 2006; Accepted 11 December 2006; Published online 23 January 2007.

Abstract

Phase III trials have demonstrated the efficacy of human papillomavirus (HPV) vaccines in preventing transient and persistent high-risk (hr) HPV infection and precancerous lesions. A mathematical model of HPV type 16 infection and progression to cervical cancer, parameterised to represent the infection in Finland, was used to explore the optimal age at vaccination and pattern of vaccine introduction. In the long term, the annual proportion of cervical cancer cases prevented is much higher when early adolescents are targeted. Vaccinating against hr HPV generates greater long-term benefits if vaccine is delivered before the age at first sexual intercourse. However, vaccinating 12 year olds delays the predicted decrease in cervical cancer, compared to vaccinating older adolescents or young adults. Vaccinating males as well as females has more impact on the proportion of cases prevented when vaccinating at younger ages. Implementing catch-up vaccination at the start of a vaccination programme would increase the speed with which a decrease in HPV and cervical cancer incidence is observed.